sg: convert the non-data path to use the block layer

This patch converts the non data path to use the block layer functions
(blk_get_request, blk_execute_rq_nowait, etc) instead of uses
scsi_execute_async().

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Douglas Gilbert <dougg@torque.net>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 48 insertions, 5 deletions

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 661f9f21650a..487c7776cc4e 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -137,6 +137,7 @@ typedef struct sg_request {	/* SG_MAX_QUEUE requests outstanding per file */
         char orphan;            /* 1 -> drop on sight, 0 -> normal */
         char sg_io_owned;       /* 1 -> packet belongs to SG_IO */
         volatile char done;     /* 0->before bh, 1->before read, 2->read */
+        struct request *rq;
 } Sg_request;
 
 typedef struct sg_fd {          /* holds the state of a file descriptor */
@@ -176,7 +177,7 @@ typedef struct sg_device { /* holds the state of each scsi generic device */
 static int sg_fasync(int fd, struct file *filp, int mode);
 /* tasklet or soft irq callback */
 static void sg_cmd_done(void *data, char *sense, int result, int resid);
-static int sg_start_req(Sg_request * srp);
+static int sg_start_req(Sg_request *srp, unsigned char *cmd);
 static void sg_finish_rem_req(Sg_request * srp);
 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
 static int sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp,
@@ -229,6 +230,11 @@ static int sg_allow_access(struct file *filp, unsigned char *cmd)
                                   cmd, filp->f_mode & FMODE_WRITE);
 }
 
+static void sg_rq_end_io(struct request *rq, int uptodate)
+{
+        sg_cmd_done(rq->end_io_data, rq->sense, rq->errors, rq->data_len);
+}
+
 static int
 sg_open(struct inode *inode, struct file *filp)
 {
@@ -732,7 +738,8 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp,
         SCSI_LOG_TIMEOUT(4, printk("sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
                           (int) cmnd[0], (int) hp->cmd_len));
 
-        if ((k = sg_start_req(srp))) {
+        k = sg_start_req(srp, cmnd);
+        if (k) {
                 SCSI_LOG_TIMEOUT(1, printk("sg_common_write: start_req err=%d\n", k));
                 sg_finish_rem_req(srp);
                 return k;       /* probably out of space --> ENOMEM */
@@ -765,6 +772,12 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp,
         hp->duration = jiffies_to_msecs(jiffies);
 /* Now send everything of to mid-level. The next time we hear about this
    packet is when sg_cmd_done() is called (i.e. a callback). */
+        if (srp->rq) {
+                srp->rq->timeout = timeout;
+                blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
+                                      srp->rq, 1, sg_rq_end_io);
+                return 0;
+        }
         if (scsi_execute_async(sdp->device, cmnd, hp->cmd_len, data_dir, srp->data.buffer,
                                 hp->dxfer_len, srp->data.k_use_sg, timeout,
                                 SG_DEFAULT_RETRIES, srp, sg_cmd_done,
@@ -1634,8 +1647,32 @@ exit_sg(void)
         idr_destroy(&sg_index_idr);
 }
 
-static int
-sg_start_req(Sg_request * srp)
+static int __sg_start_req(struct sg_request *srp, struct sg_io_hdr *hp,
+                          unsigned char *cmd)
+{
+        struct sg_fd *sfp = srp->parentfp;
+        struct request_queue *q = sfp->parentdp->device->request_queue;
+        struct request *rq;
+        int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
+
+        rq = blk_get_request(q, rw, GFP_ATOMIC);
+        if (!rq)
+                return -ENOMEM;
+
+        memcpy(rq->cmd, cmd, hp->cmd_len);
+
+        rq->cmd_len = hp->cmd_len;
+        rq->cmd_type = REQ_TYPE_BLOCK_PC;
+
+        srp->rq = rq;
+        rq->end_io_data = srp;
+        rq->sense = srp->sense_b;
+        rq->retries = SG_DEFAULT_RETRIES;
+
+        return 0;
+}
+
+static int sg_start_req(Sg_request *srp, unsigned char *cmd)
 {
         int res;
         Sg_fd *sfp = srp->parentfp;
@@ -1646,8 +1683,10 @@ sg_start_req(Sg_request * srp)
         Sg_scatter_hold *rsv_schp = &sfp->reserve;
 
         SCSI_LOG_TIMEOUT(4, printk("sg_start_req: dxfer_len=%d\n", dxfer_len));
+
         if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
-                return 0;
+                return __sg_start_req(srp, hp, cmd);
+
         if (sg_allow_dio && (hp->flags & SG_FLAG_DIRECT_IO) &&
             (dxfer_dir != SG_DXFER_UNKNOWN) && (0 == hp->iovec_count) &&
             (!sfp->parentdp->device->host->unchecked_isa_dma)) {
@@ -1678,6 +1717,10 @@ sg_finish_rem_req(Sg_request * srp)
                 sg_unlink_reserve(sfp, srp);
         else
                 sg_remove_scat(req_schp);
+
+        if (srp->rq)
+                blk_put_request(srp->rq);
+
         sg_remove_request(sfp, srp);
 }